Yes, there are lots of little screamers out there, but just once in a while you meet an example of how good children can be. Some time ago now on longhaul I was sitting next to the parents with their three children, probably in the range 8-12, in the row in front of me. the only time I heard from them was when one or other put their head over the seat and quietly asked for somehting else to keep them amused. No hassle no noise.
Well behaved children and parents prepared with things to keep them amused - pleasant flight for all.
The parents got a complement from me on arrival
D.